Integral gear



April 1966 a. M. MOONEY 3,245,280

INTEGRAL GEAR Original Filed Jan. 14, 1963 2 Sheets-Sheet 1 INVENTORGEORGEM Moo/v5) WMMX ATTORNEYS April 12, 1966 G. M. MOONEY 3,245,280

INTEGRAL GEAR Original Filed Jan. 14, 1963 2 Sheets-Sheet 2 I NVEN TOR.GEoRsEM Mao/war A'r-I-ORNEK;

United States Patent 4 Claims. c1. 74--462) This is a division ofapplication Serial No. 251,168, filed January 14, 1963.

This invention relates to an integral composite polyfunctional toothedworking part, such as a gear. More particularly, this invention relatesto an integral composite polyfunctional working part, such as a gear,having at least two separate operating concentric toothed annular faces,which are separate and spaced apart or offset with respect to oneanother. For convenience, the invention is described and illustratedwith specific reference to a combination bevel gear and clutch of a typeuseful in reverse gear mechanisms.

The invention is illustrated with reference to the drawings in whichlike numerals refer to corresponding parts and in which:

FIGURE 1 is a plan view of an integral bevel gear and clutch accordingto the present invention;

FIGURE 2 is a section on the line 2-2 of FIGURE 1 and in the directionof the arrows;

FIGURE 3 is a plan view of the working face of an integral bevel gearand clutch showing diagrammatically the manner in which the ratchetteeth of the clutch plate are formed;

FIGURE 4 is a section on the line 4-4 of FIGURE 3 and in the directionof the arrows; and

FIGURE 5 is a partial plan view on an enlarged scale of a portion of theworking face of the clutch to show details.

Referring to the drawings, the one-piece integral composite gear'andclutch, indicated generally at 10, includes a hub 11 by means of whichthe integral structure is mounted in bearings or fitted to the end of ashaft. Radial holes 12 in the hub are provided to hold the work piece ina jig during cutting of the teeth. The end of the jig shaft may bottomon an annular shoulder 14. The face of the integral gear and clutch isprovided with an annular ring of a plurality of radiating beveled gearteeth 15 by milling in the conventional manner.

The clutch portion of the integral composite structure includes aplurality of tapered arcuate ratchet teeth 17 disposed in an annulararray concentric with and within the inner periphery of the bevel gearand recessed or spaced from the plane generated by the top-most surfacesof the bevel gear teeth. This is clearly apparent in FIGURE 2. The planeof the highest surfaces of the bevel gear teeth is there indicated bythe broken line designated by numeral 18.

Each ratchet tooth face of the clutch is in the form of an arcuatesloping surface extending from a peak or crown or ridge 19 to a valleyor channel 20. The engaging face 21 of each ratchet tooth lies generallyalong a radial plane extending through the longitudinal center line oraxis of rotation of the composite unit. However, as more clearly seen inFIGURE 5, the engaging face 21 is preferably provided with a slightconvexity to form a small crown. The outer peripheral edge of eachratchet tooth abuts against and is integral with the inner periphery ofthe bevel gear. This contributes to the added strength of the compositeunit.

Combination gears and clutches of the type described have been knownheretofore. However, because of fabrication problems these prior unitshave always been made as separate parts and then secured together insome 3,245,230 Patented Apr. 12, 1966 convenient manner. For example,the ratchet and bevel gear were separately formed, and then brazedtogether; or the ratchet was first formed and a bevel gear blank wasthen brazed to it, and, thereafter, the gear teeth were generated. Insuch two piece construction the bevel gear and ratchet were brazedgenerally along the broken line indicated at 22 in FIGURE 2, the bevelgear being supported on shoulder 23 of the ratchet.

The reason why this means of fabrication was necessary is that it wasnot possible to cut the ratchet teeth by existing tooth cutting meansbecause of the offset recessed or depressed relationship between theratchet teeth of the clutch and the teeth of the bevel gear. In otherwords, the area of the work blank in which the ratchet teeth were to beformed was inaccessible by ordinary tooth cutting means utilizingrevolving disc or wheel type cutters. By forming the parts separately nosuch problem existed. The ratchet teeth of the clutch, when separatedfrom the bevel gear, were formed in the conventional manner byconventional tooth cutting means.

For many years the two part brazed structures were satisfactory inservice. However, with increasing horsepower the composite gears andclutches are subjected to greater forces, with the result that shearingoccurred at the site of the braze between the gear and clutch. Previousattempts to strengthen the composite gear and clutch structure have notbeen successful.

Thereupon, the integral composite gear and clutch according to thepresent invention was conceived but such structure was impossible ofmanufacture by existing tooth cutting means because of theinaccessibility of the work piece by the cutting tool in the area of theratchet teeth. Accordingly, the method as illustrated in FIGURES 3 and 4was conceived as a means of overcoming the seemingly insurmountablefabrication problem.

According to that method, the work piece is machined to outline shapefrom steel bar stock of appropriate quality and strength. The resultingwork piece is held in a suitable jig at an angle with respect to acutting tool 25 corresponding to the desired slope of the face surfaceof the ratchet teeth. The end cutting face of the tool 25 is broughtinto contact with the work piece and cuts the ratchet tooth surface by acombination of the relative rotational movement of the cutter about itsown axis and rotational movement of the work piece about its own axisthrough an are dependent upon the desired number of ratchet teeth.

The channel or valley 20 between adjacent ratchet teeth and the engagingface 21 of each ratchet tooth is formed by another side milling cutter27 having cutting faces at its edges. Cutter 27 is positioned relativeto the work piece so that the axis of rotation of that cutter variesfrom generally parallel to the axis of rotation of the finished integralgear and clutch to about 8 or so away from the axis of rotation of thefinished part. Cutter 27 and the work piece move relative to one anotheralong a path lying generally along a radius of the work piece. However,as shown in FIGURE 4, cutter 27 and the work piece preferably moverelative to one another along a very slightly arcuate path to producethe desired crown on the engaging face 21. Each cutting operation isrepeated to complete the required number of ratchet teeth. The edgebetween ratchet tooth ridge 19 and engaging face 21 is preferablychamfered. Because the bevel gear teeth 15 are out in an exposedaccessible portion of the work piece, the bevel gear teeth are producedby conventional tooth cutting means in the conventional manner. Thebevel gear teeth may be generated before or after the ratchet teeth, butpreferably afterward.

In FIGURE 5 there is shown on an enlarged scale the portion of the planview of FIGURE 3 included within broken line circle 28 in order to showmore precisely the ice preferred construction of the ratchet toothengaging faces 21. In order to concentrate the load of the force exertedupon the clutch teeth by an engaging clutch dog in the center of theteeth it is desirable that the engaging faces of the teeth be providedwith a slight convex crown. In order to produce such a crown accordingto the specifications of the designer of the mechanism in which the gearand clutch is used, cutter 27 is moved relative to the work piece alongan arcuate path of large radius. This produces the very slight convexcurvature of the engaging face 21 as shown in the enlarged detail viewof FIGURE 5. As an example of design specifications in this regard, onerequirement is that the surface of the engaging face 21 of the ratchettooth have a crown of 0.002 inch in a inch length and that the crown becentered in the shaded zone 29. Obviously the height of the crown can bevaried to meet specific requirements. Similarly, the degree ofinclination of the engaging faces of the ratchet teeth from the radialplane extending through the longitudinal center line of the integralgear and clutch may be varied to meet design specifications. In theexample given, the engaging face 21 is inclined 5 inwardly from the edgewith ridge 19.

Although the invention is described and illustrated by specificreference to a combined bevel gear and clutch, it will be apparent thatthe principles are applicable to any composite integral toothedstructure in which the toothed engaging faces are offset or displacedwith respect to one another such that one set of teeth are in a locationwhich is inaccessible by conventional tooth cutting means. The inventionis obviously not limited to any particular size or shape or arrangementof gear teeth, or for a working part for the purpose of performing anyspecific function or a working part for use in any particular mechamsm.

It is apparent that many modifications and variations of this inventionas hereinbefore set forth may be made Without departing from the spiritand scope thereof. The specific embodiments described are given by wayof example only and the invention is limited only by the terms of theappended claims.

I claim:

1. As a new article of manufacture, a one piece integral composite gearand clutch adapted for rotation about an axis, said gear and clutchincluding an unobstructed annular ring of a plurality of gear teethdisposed about said axis of rotation and an annular ring of a pluralityof arcuate sloping ratchet teeth concentric with and within the innerperiphery of said ring of gear teeth, said ratchet teeth being recessedrelative to said gear teeth, each of said ratchet teeth having agenerally radial engaging face extending generally along a line passingthrough said axis of rotation, the engaging face of each of said ratchetteeth being slightly arcuate to provide a low convex crown in theapproximate center of each engaging face.

2. An article of manufacture according to claim 1 further characterizedin that said gear is a bevel gear.

3. An article of manufacture according to claim 1 further characterizedin that the engaging face of each of said ratchet teeth is inclinedinwardly from the ridge of each of said teeth by up to about 8.

4. As a new article of manufacture, a one piece integral composite gearand clutch adapted for rotation about an axis, said gear and clutchincluding an unobstructed annular ring of a plurality of gear teethdisposed about said axis of rotation and an annular ring of a pluralityof arcuate sloping ratchet teeth concentric with and within the innerperiphery of said ring of gear teeth, said ratchet teeth being recessedrelative to said gear teeth, each of said ratchet teeth having agenerally radial engaging face extending generally along a line passingthrough said axis of rotation, the engaging face of each of said ratchetteeth being inclined inwardly from the ridge of each of said teeth by upto about 8".

References Cited by the Examiner UNITED STATES PATENTS 2,289,288 7/1942Kauffman 74378 DON A. WAITE, Primary Examiner.

1. AS A NEW ARTICLE OF MANUFACTURE, A ONE PIECE INTEGRAL COMPOSITE GEARAND CLUTCH ADAPTED FOR ROTATION ABOUT AN AXIS, SAID GEAR AND CLUTCHINCLUDING AN UNOBSTRUCTED ANNULAR RING OF A PLURALITY OF GEAR TEETHDISPOSED ABOUT SAID AXIS OF ROTATION AND AN ANNULAR RING OF A PLURALITYOF ARCUATE SLOPING RATCHET TEETH CONCENTRIC WITH AND WITHIN THE INNERPERIPHERY OF SAID RING OF GEAR TEETH, SAID RATCHET TEETH BEING RECESSEDRELATIVE TO SAID GEAR TEETH, EACH OF SAID RATCHET TEETH HAVING AGENERALLY RADIAL ENGAGING FACE EXTENDING GENERALLY ALONG A LINE PASSINGTHROUGH SAID AXIS OF ROTATION, THE ENGAGING FACE OF EACH OF SAID RATCHETTEETH BEING SLIGHTLY ARCUATE TO PROVIDE A LOW CONVEX CROWN IN THEAPPROXIMATE CENTER OF EACH ENGAGING FACE.